python simplejson decoding

[Felipe Vinturini]

Hi Arthur,

Maybe this link helps you: http://www.doughellmann.com/PyMOTW/json/

<http://www.doughellmann.com/PyMOTW/json/>I used it to learn JSON. =o)

Regards,
Felipe.

On Wed, Mar 2, 2011 at 11:24 AM, Peter Otten <__peter__ at web.de> wrote:

> Arthur Mc Coy wrote:
>
> > Hi all,
> >
> >
> >
> > I'm trying an example (in attached file, I mean the bottom of this
> > message).
> >
> > First, I create a list of 3 objects. Then I do:
> >
> >
> > PutJSONObjects(objects)
> > objects = GetJSONObjects()
> > PutJSONObjects(objects, "objects2.json")
> >
> >
> > 1) PutJSONObjects(objects) method creates objects.json file (by
> > default). It works fine.
> > 2) Then objects = GetJSONObjects() method get the file contents and
> > return.
> >
> > 3) Finally the script fails on the third method
> > PutJSONObjects(objects, "objects2.json")
> > saying: AttributeError: 'dict' object has no attribute '__dict__'
> >
> >
> > That is true, because objects returned by GetJSONObjects() is not a
> > list of objects, but simple string....
> >
> > So here is the question, please, how should I DECODE .json file into
> > list of python objects so that I will be able to put the copy of these
> > objects into a new file called objects2.json ?
> >
> > simplejson docs are hard to follow - without examples.
>
> I suggest that you use json instead which is part of the standard library
> since Python 2.6. The documentation is here:
>
> http://docs.python.org/library/json.html
>
> If you know that there are only MyObject instances you need a function to
> construct such a MyObject instance from a dictionary. You can then recreate
> the objects with
>
> objects = [object_from_dict(d) for d in json.load(f)]
>
> or, if all dictionaries correspond to MyObject instances
>
> objects = json.load(f, object_hook=object_from_dict)
>
> A general implementation for old-style objects (objects that don't derive
> from object) is a bit messy:
>
> # idea copied from pickle.py
> class Empty:
>    pass
>
> def object_from_dict(d):
>    obj = Empty()
>    obj.__class__ = MyObject
>    obj.__dict__.update((str(k), v) for k, v in d.iteritems()) # *
>    return obj
>
> If you are willing to make MyClass a newstyle class with
>
> class MyObject(object):
>    # ...
>
> the function can be simplified to
>
> def object_from_dict(d):
>    obj = object.__new__(MyObject)
>    obj.__dict__.update((str(k), v) for k, v in d.iteritems()) # *
>    return obj
>
> (*) I don't know if unicode attribute names can do any harm,
> obj.__dict__.update(d) might work as well.
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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